SNESNGMRES#

The Nonlinear Generalized Minimum Residual method.

Options Database Keys#

  • -snes_ngmres_select_type<difference,none,linesearch> - choose the select between candidate and combined solution

  • -snes_ngmres_restart_type<difference,none,periodic> - choose the restart conditions

  • -snes_ngmres_candidate - Use SNESNGMRES variant which combines candidate solutions instead of actual solutions

  • -snes_ngmres_m - Number of stored previous solutions and residuals

  • -snes_ngmres_restart_it - Number of iterations the restart conditions hold before restart

  • -snes_ngmres_gammaA - Residual tolerance for solution select between the candidate and combination

  • -snes_ngmres_gammaC - Residual tolerance for restart

  • -snes_ngmres_epsilonB - Difference tolerance between subsequent solutions triggering restart

  • -snes_ngmres_deltaB - Difference tolerance between residuals triggering restart

  • -snes_ngmres_restart_fm_rise - Restart on residual rise from x_M step

  • -snes_ngmres_monitor - Prints relevant information about the ngmres iteration

  • -snes_linesearch_type <basic,l2,cp> - Line search type used for the default smoother

  • -additive_snes_linesearch_type - linesearch type used to select between the candidate and combined solution with additive select type

Notes#

The N-GMRES method combines m previous solutions into a minimum-residual solution by solving a small linearized optimization problem at each iteration.

Very similar to the SNESANDERSON algorithm.

References#

  • **** -*** C. W. Oosterlee and T. Washio, “Krylov Subspace Acceleration of Nonlinear Multigrid with Application to Recirculating Flows”, SIAM Journal on Scientific Computing, 21(5), 2000.

  • **** -*** Peter R. Brune, Matthew G. Knepley, Barry F. Smith, and Xuemin Tu, “Composing Scalable Nonlinear Algebraic Solvers”, SIAM Review, 57(4), 2015

See Also#

SNESCreate(), SNES, SNESSetType(), SNESType, SNESANDERSON, SNESNGMRESSetSelectType(), SNESNGMRESSetRestartType(), SNESNGMRESSetRestartFmRise()

Level#

beginner

Location#

src/snes/impls/ngmres/snesngmres.c

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